Motor



Jan. 6, 1942 s. w. BLESSING MOTOR Filed Sept. 1, 1959 6 7 270 jffib zcryor Patented Jan. 6, 194 2 MOTOR *Gregory W. Blessing, Moorestown, N. 1.,assignor to Radio Corporation of America, a corporation of DelawareApplication September 1, 1939, Serial No. 292,998

6 Claims.

This invention relates to electric motors of the synchronous type, andmore particularly to a motor adapted for use especially in phonographicapparatus, the present invention being an improvement upon thosedisclosed in Patents Nos. 2,113,384 and 2,157,158.

In each of these patents, there is disclosed a synchronous motor havinga rigid frame which supports the operating parts of the motor and whichis secured to the motor board of the phonograph, usually by a pluralityof screws and bolts. In order to prevent mechanical vibrations arisingin the motor from reaching the motor board, so that the pickup mechanismalso carried by the motor board will not be aiiected by such vibrations,it has been customary to interpose between the frame and the motor boardcoupling elements including rubber cushions and grommets, therebynecessitating also the use of spacers, washers, etc., for eilicientlymounting the motor. This not only has the effect of considerably slowingup assembly during production, but also adds to the cost of assembly.

In another form of motor, such as that, for example, disclosed in thecopending application of Emile C, Guedon, Serial No. 222,167, filed July30, 1938, and assigned to the Radio Corporation of America, now PatentNo. 2,201,251, the hub which supports the stator is provided with arubber sleeve or bushing which is also intended to vibration-insulatethe fixed parts of the motor from the motor board to preventtransmission of vibrations to the latter and through it to the pickup.Here, again, therefore, there is involved an expense and time necessaryfor proper assembly of the parts.

The primary object of my present invention is to provide an improvedmotor and mounting of the typ under consideration which is of greatlysimplified construction and which may be assembled with great speed andfacility.

More particularly, it is an object of my present invention to provide animproved motor and" mounting therefor whichcomprises a minimum number ofparts and which can be readily as- 45 sembled even by one who isunskilled in such practice.

It is also an object of my present invention to provide a motor andmounting therefor as aforesaid which is extremely inexpensive in cost,which is highly efficient in use, and which has a long life.

In accordance with my ,present invention, I provide a frame for themotor which comprises merely three radially extending arms or rods whichare secured to the hub of the motor and which are received in resilientcoupling members on the motor board, the resilient coupling membersbeing made 'of rubber and constituting the sole connection between theframe and the motor board. These coupling members are received inradially extending slots of the motor board and are preferably T-shaped,having greater dimensions in a radial direction and in a directionnormal to the plane of the motor board then in a transverse direction,or in a circumferential direction with respect to the motor axis. Thus,the coupling members are relatively rigid in the former two directionsbut relatively yieldable in the latter directions, so that the frame iscapable of slight circumferential movement relative to the motor boardbut without'transmitting any oscillations to the motor board and theparts carried thereby.

The novel features that Iconsider characteristic of my invention are setforth with particularity in the appended claims. The invention itself,however, both as to its organization and method of operation, togetherwith additional objects and advantages thereof, will best be understoodirom'the following description of one embodiment thereof, when read inconnection with the accompanying drawing in which--- Figure 1 is a topplan view of a phonograph embodying one form of my invention,

Figure 2 is a sectional view thereof taken alongthe line II--II ofFigure 1, and

Figure 3 is a perspective view of one of the coupling members'betweenthe motor frame and the motor board.

Referring more particularly to the drawing,

wherein similar reference characters designate,

corresponding parts throughout, I have shown a cabinet I having arecessed motor board 3 40 formed with a relatively large opening 5 andwith a plurality of radially extending slots I communicating with theopening 5. In each of the slots 1, there is frictibnally received arubber coupling member 9 preferably of T-shape and preferably so formedthat it has much greater dimensions along the lengths a and b than alongits thickness 0. Thus, the coupling members 8 are relatively flexiblealong the thickness 0 but relatively inflexible along the lengths a andb, and this is for a p p presently to be set forth.

Frictionally received within openings II in the coupling members 9 arethe ends of a plurality of arms I: equally spaced about and extendingradially from the hub ll of a motor.

5 The motor is preferably of the synchronoustype disclosedin theabove-noted patents and includes abushing l'l withinthebubllandinwhichis rotatably mounted a spindle is carrying arecord-supporting turntable Ii. Fixed to the upper end of the bushing i1is a stator, provided with, a plurality of peripheral teeth 28constituting pole faces and having'a pair of energizing coils 21 mountedthereon. The motor also includes an annular rotor is surrounding thestator I! and provided with a series of internal teeth Ii ofsubstantially the same arcuat'e length as the teeth II, the teeth llcooperating with the teeth II to constitute cooperating pole faces.

The rotor 2| preferably has secured thereto a disc-like member 38 whichmay be connected to the turntable II in the manner disclosed and claimedin my 'copendlng application, Serial No.

202,907 filed September 1, 1989, now Patent No.-

2,!47548. A spring ll secured to one of the arms II and extendingupwardly through the stator 2! serves to restrain 'the stator againstoscillation.

In assembling the motor on the motor board, the rubber coupling membersI are slipped onto theendsoftheradialarms ilconstitutingthe frame of themotor, after which assembly is mounted on the motor board 8 by plyressing the legs of the members I downwardly through the slots "I tosuspend the motor from the motor board I. By properly dimensioning themembers a and the slots I, it is obvious that the motor will becomeautomatically centered in the opening I which receives the statorandrotor structure. The assembly is carried out quickly and with greatfacility, and, when once in place, will hold the motor firmLv again tmovement in aradialdirectionaswellasinadirectionnormal to the plane ofthe motor board 3. However, be-

cause of the relative flexibility of the downwardly extending legs ofthecoupling members I in a circumferential direction relativetothe ads of:

thespindle it (that is. along the length 0). it'isobviousthatanytendencyforthemotorframetovibrateinsuchdirectionwillhavenoeflectuponthemotorboard,inaunuchasthevlbrationsor:tiirionswillbereadllyabsorbedbythemem-Aithoughlhaveshownanddescribedbutoneqnbodimentofmyinventiomitwillbeobviousto.

those skllledin the art that many other modiil cations thereof andchanges therein are possible. For example. the members l need not be I;shaped, but may be of any other desired formaticn. such as cylindrical,for example. and formed with an enlarged head corresponding to the crossheads of the nfembers I ,to prevent them from slipping through the motorboard. Also, the slots I 'need not be made to communicate with theopeningl,ifthisisnotdesired. Manyother changes will be obvious to thoseskilled in the art. I desire, therefore, that my invention shall not belimited except insofar as is made necessary :ly the prior art and by thespirit of the app nded coupling members, and said coupling membersconstituting the sole connection between said frame and said motorboard.

2. The invention set forth in claim 1 characterised in that saidcoupling members are of greater dimension in a radial direction thanln acircumferential direction relative to the axis of the mofir whereby saidcoupling members will yield more readily in said circumferentialdirection in said radial direction.

3. The invention set forth in claim 1 characteriaed in that saidcoupling membersare of greater dimension in a direction normal to theplane of said motor d than in'a circumferential direction relat ve tothe axis of the motor whereby said coupling members will yield morereadily in said last-named direction than in said firstnamed direction.

4. .In combination, a motor. board having a plurality of openingstherein, and a rubber member frictionally fitted in each of saidopenings for supporting a motor, said members each having a relativelygreater height and depth than thickness and being so arranged on saidmotor board that the, height 1 thereof extends substantially parallel tothe motor axis, the depth thereof extends substantially radially of themotor, and the thickness thereof extends substantially circumferentiallyof the motor.

5. The invention set forth in claim 4 charac-- T-shaped cross section,and characterized further in that said members are so arranged with saidopenings that the heads of the T's engage said motor boardto preventsaid members from slipping through said openings.

GREGORY W. BLEBBING.

